Power operated fastener driving tools are traditionally used in industrial applications where compressed air provides a convenient power source. Because of the nature of the compressed air power source and the expense involved in heavy duty industrial fastener driving tools, such tools are generally not suitable for use in fastening jobs where maneuvering is required, space is limited, or compressed air is not available. Manually operated fastener driving tools are also used in industrial applications. However, in many of the jobs where manually operated fastener driving tools are used, considerable operator fatigue may be involved because a manual fastener driving tool requires a large user actuation force.